For the blueberry swirl:

In a small pot over medium-low heat, add the blueberries, sugar, and water. As the mixture begins to boil, use a whisk or potato masher to break up the blueberries. Cook for 4-5 minutes or until the mixture slightly thicken.

Use a fine mesh sieve to strain the mixture, pressing lightly on the pulp to release as much syrup as possible. Set aside to cool completely.

For the ice cream:

Place the heavy cream, sweetened condensed milk, lemon juice, lemon zest, and limoncello in the bowl of a stand mixer. Start on low speed to combine the ingredients then slowly raise the speed to medium. Whisk until soft peaks form and the mixture is airy.

In a wide-top container or a 9″ x 5″ loaf pan, pour in half of the ice cream base. Layer on half of the blueberry syrup. Using a wooden skewer or butter knife, gently swirl the blueberry syrup into the ice cream – do not overmix.

Repeat with the remaining ice cream base and blueberry syrup. Cover the container (or cover the loaf pan with plastic wrap). Place in the freezer for 6 hours or overnight.